Various types of implanted medical devices, such as implanted drug pumps, are used to deliver controlled volumes of a therapeutic fluid substance (e.g. a drug) within a patient's body. These pumps generally have reservoirs that may be accessed through ports, which may be self-sealing and may provide a drug suspension or solution from the device.
After the medical device is implanted within a patient, it may be desirable to fill, refill, flush out, or change fluid in a reservoir or other portion of the device. Typically, this is accomplished by a health care provider (HCP), for example, a clinician. The HCP typically locates the device access port by palpitating a patient's skin, as the access port typically protrudes from the infusion pump. The HCP then inserts a needle or similar device advancing through the patient's skin into the implanted device to dispense or remove the intended therapeutic fluid substance.
Because the implanted medical device cannot be directly viewed, care must be taken to ensure proper needle placement into the device before injecting a therapeutic substance. If the needle misses the device, the therapeutic substance may be dispensed in the patient's body resulting in delivery of an improper amount and at an improper location, with potentially adverse consequences for the patient.